U.S. patent application number 16/493225 was filed with the patent office on 2020-03-26 for fluoropolymer articles and related methods.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Moses M. David, Timothy J. Hebrink, Chris A. Praggastis, Pingfan Wu.
Application Number | 20200094537 16/493225 |
Document ID | / |
Family ID | 62599676 |
Filed Date | 2020-03-26 |
![](/patent/app/20200094537/US20200094537A1-20200326-D00000.png)
![](/patent/app/20200094537/US20200094537A1-20200326-D00001.png)
![](/patent/app/20200094537/US20200094537A1-20200326-D00002.png)
![](/patent/app/20200094537/US20200094537A1-20200326-D00003.png)
United States Patent
Application |
20200094537 |
Kind Code |
A1 |
Wu; Pingfan ; et
al. |
March 26, 2020 |
Fluoropolymer Articles and Related Methods
Abstract
Provided are surfacing films that have a surface layer having
opposed first and second major surfaces, the first major surface
comprising a fluoropolymer surface and the second major surface
optionally comprising a nanostructured surface. A printed layer can
be disposed on the second major surface and can be at least
partially embedded in the nanostructured surface, if present. As a
further option, the fluoropolymer surface can be microreplicated to
provide a frictional surface and/or provide aerodynamic drag
reduction on aircraft structures. Optionally, the delamination peel
strength of the surface layer from the remaining layers can be
greater than the tensile strength of the surface layer.
Inventors: |
Wu; Pingfan; (Woodbury,
MN) ; Hebrink; Timothy J.; (Scandia, MN) ;
David; Moses M.; (Woodbury, MN) ; Praggastis; Chris
A.; (Renton, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
62599676 |
Appl. No.: |
16/493225 |
Filed: |
May 3, 2018 |
PCT Filed: |
May 3, 2018 |
PCT NO: |
PCT/US2018/030844 |
371 Date: |
September 11, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62504143 |
May 10, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 3/30 20130101; B32B
2605/18 20130101; B32B 27/304 20130101; B32B 2260/02 20130101; B32B
2260/046 20130101; B32B 2571/00 20130101; B32B 7/10 20130101; B32B
2307/748 20130101; B32B 3/00 20130101; B32B 2255/10 20130101; B32B
7/12 20130101; B32B 27/08 20130101; B32B 2310/14 20130101; B32B
2553/00 20130101; B32B 2255/26 20130101; B32B 27/40 20130101; B32B
27/308 20130101 |
International
Class: |
B32B 27/30 20060101
B32B027/30; B32B 27/40 20060101 B32B027/40; B32B 3/30 20060101
B32B003/30; B32B 7/12 20060101 B32B007/12; B32B 7/10 20060101
B32B007/10 |
Claims
1. A surfacing film comprising: a surface layer having opposed
first and second major surfaces, the first major surface comprising
a fluoropolymer surface and the second major surface comprising a
nanostructured surface; and a printed layer disposed on the second
major surface and at least partially embedded in the nanostructured
surface.
2. The surfacing film of claim 1, wherein the nanostructured
surface comprises a plasma reactive ion etched surface.
3. The surfacing film of claim 1, further comprising an adhesive
layer extending across at least a portion of the printed layer.
4. The surfacing film of claim 3, further comprising a support
layer disposed between the adhesive layer and the printed
layer.
5. The surfacing film of claim 4, wherein the support layer
comprises polyurethane or poly(methyl methacrylate).
6. The surfacing film of claim 1, wherein the first major surface
has a microreplicated surface.
7. The surfacing film of claim 6, wherein the microreplicated
surface comprises a plurality of ridges defining capillary
channels.
8. The surfacing film of claim 1, wherein the support layer is
pigmented, the printed layer is discontinuous, and the support
layer is at least partially embedded in the nanostructured
surface.
9. (canceled)
10. (canceled)
11. A surfacing film comprising: a surface layer having opposed
first and second major surfaces, the first major surface comprising
a fluoropolymer surface; a tie layer underlying the surface layer,
wherein the surface layer and the tie layer are coextruded layers;
and a printed layer disposed on the tie layer.
12. A surfacing film comprising: a surface layer having opposed
first and second major surfaces; and an adhesive layer extending
across the second major surface, wherein the first major surface
comprises a fluoropolymer surface comprises a microreplicated
surface and wherein delamination peel strength of the surface layer
from the remaining layers is greater than the tensile strength of
the surface layer based on the 180.degree. Peel Test.
13. The surfacing film of claim 1, wherein the fluoropolymer
surface comprises a copolymer of vinylidene fluoride and
hexafluoropropylene.
14. A method of using the surfacing film of claim 1, comprising
applying the surfacing film to an outer surface of an aircraft
component to enhance friction.
15. (canceled)
Description
FIELD OF THE INVENTION
[0001] Provided are articles having fluoropolymer surfaces and
methods of making and using the same. The provided articles can be
deployed as surfacing films disposed on external surfaces of a
substrate.
BACKGROUND
[0002] Surface films are free-standing films that can be applied to
a given substrate and can serve any of a number of purposes.
Materials used for such surface films and their configurations can
vary widely based on the industrial or commercial application at
hand.
[0003] Some surface films are primarily intended to provide surface
protection against environmental factors such as rain erosion,
sand, or other impacts normally encountered by the substrate during
use. Surface protection films can be used, for example, to protect
the painted surfaces of automobile, marine, or aircraft body parts.
Protective films that use one or more layers of a polyurethane are
known, and described in U.S. Pat. No. 5,405,675 (Sawka et al.), in
U.S. Pat. No. 5,468,532 (Ho et al.), in U.S. Pat. No. 6,383,644
(Fuchs), and in U.S. Pat. No. 6,607,831 (Ho et al.).
[0004] Other films have aerodynamic applications, such as
drag-reduction films that are used on the leading surfaces of
aircraft to guide air flow over these surfaces and minimize
turbulence. Surface features capable of reducing aerodynamic drag
are described in U.S. Pat, No. 5,971,326 (Bechert), in U.S. Pat.
No. 8,668,166 (Rawlings et al.), and in U.S. Pat. No. 8,678,316
(Rawlings et al.).
[0005] Other films have functions that may be primarily aesthetic
or graphical in nature--for example, such films could include
decorative films used on stainless steel appliances,
point-of-purchase displays, plastic extrudate, and commercial
graphic films on wall surfaces. Any of these films may be pigmented
and color matched to achieve a customized appearance. If such a
film is to be disposed on a walking surface, then it may be
desirable for a film to provide a frictional surface to prevent
pedestrian slippage.
[0006] Any combination of the above may be represented in the
performance criteria for a given surface film.
SUMMARY
[0007] The engineering of a surface film to retain its functional
and aesthetic properties under long-term exposure to harsh
environments has been and continues to be a significant technical
challenge. Such environments not only include exposure to natural
elements such as rain, salt spray, and sand, but also solvents and
other chemicals used in operating or cleaning the structures to be
protected.
[0008] In aerospace applications, polymeric surface films often
have limited resistance to hydraulic fluids such as SKYDROL
fire-resistant hydraulic fluids, which are generally based on
phosphate esters. Commonly used polymers, such as polyurethanes,
can soften and degrade with exposure to SKYDROL hydraulic fluids.
Moreover, cleaning fluids contain solvents that can erode certain
polymeric surface films.
[0009] As another example, surfacing tapes often have problems with
delamination. Surface films are generally fastened to their
underlying substrate surface using an adhesive, such as a
pressure-sensitive adhesive. While delamination in one piece may be
desirable for ease of removal in controlled environments, such
delamination from an aircraft surface in flight can result in the
film being trapped by a fin or stabilizer. Such a situation could
cause loss of control of the aircraft.
[0010] The surfacing films disclosed herein provide an answer to
some of these technical shortcomings. These films use a surfacing
layer with a fluoropolymer surface that can provide an edge seal
against rain erosion and chemical resistance. In some embodiments,
these films tend to fragment when removed and resist delamination
in one piece when adhered to common substrates.
[0011] In a first aspect, a surfacing film is provided. The
surfacing film comprises: a surface layer having opposed first and
second major surfaces, the first major surface comprising a
fluoropolymer surface and the second major surface comprising a
nanostructured surface; and a printed layer disposed on the second
major surface and at least partially embedded in the nanostructured
surface.
[0012] In a second aspect, a surfacing film is provided,
comprising: a surface layer having opposed first and second major
surfaces, wherein the first major surface comprises a fluoropolymer
surface; and a microreplicated intermediate layer in contact with
the second major surface, wherein the fluoropolymer surface has a
microreplicated surface at least partially shaped by the
microreplicated intermediate layer.
[0013] In a third aspect, a surfacing film is provided, comprising:
a surface layer having opposed first and second major surfaces, the
first major surface comprising a fluoropolymer surface; a tie layer
underlying the surface layer, wherein the surface layer and the tie
layer are coextruded layers; and a printed layer disposed on the
tie layer.
[0014] In a fourth aspect, a surfacing film is provided comprising:
a surface layer having opposed first and second major surfaces; and
an adhesive layer extending across the second major surface,
wherein the first major surface comprises a fluoropolymer surface
comprises a microreplicated surface and wherein delamination peel
strength of the surface layer from the remaining layers is greater
than the tensile strength of the surface layer based on the
180.degree. Peel Test.
[0015] In a fifth aspect, a method of using an aforementioned
surfacing film is provided, comprising applying the surfacing film
to an outer surface of an aircraft component to enhance
friction.
[0016] In a sixth aspect, a method of making a surfacing film is
provided, the method comprising: disposing a printed layer on a
support layer to provide a bilayer; and laminating the bilayer to a
surface layer having opposing first and second major surfaces,
wherein the first major surface comprises a fluoropolymer surface
and the second major surface has a nanostructured surface and is in
contact with the printed layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1-5 are an elevational, cross-sectional views of
surfacing films according to various embodiments, with some layers
shown in exploded view for clarity.
[0018] FIG. 6 is a split photograph showing the effect of hydraulic
fluid on two different areas of a surfacing film over time.
DEFINITIONS
[0019] As used herein:
[0020] "ambient conditions" means at a temperature of 25.degree. C.
and a pressure of 1 atmosphere (i.e., 101.3 kPa);
[0021] "average" refers to a number average;
[0022] "cure" refers to chemically crosslinking, such as by
exposing to radiation in any form, heating, or allowing to undergo
a chemical reaction that results in hardening or an increase in
viscosity (e.g., under room temperature or heated conditions);
[0023] "microreplicated" means having a configuration of repeating,
three-dimensional structures where at least two dimensions of the
structures are microscopic;
[0024] "nanostructured" means characterized by topological features
having respective dimensions on a nanometer scale (for example,
between 1 nm and 500 nm);
[0025] "polymer" refers to a molecule having at least one repeating
unit and can include copolymers;
[0026] "solvent" refers to a liquid capable of dissolving a solid,
liquid, or gas, such as silicones, organic compounds, water,
alcohols, ionic liquids, and supercritical fluids; and "patterned"
means having a configuration of replicated, three-dimensional
structures.
DETAILED DESCRIPTION
[0027] Repeated use of reference characters in the specification
and drawings is intended to represent the same or analogous
features or elements of the disclosure. It is to be understood that
numerous other modifications and embodiments can be devised by
those skilled in the art and fall within the scope and spirit of
the principles of the disclosure. The figures may not be drawn to
scale.
[0028] The provided surfacing films can be useful in many
functional and/or decorative applications. In one application, the
surfacing films are primarily used to prevent erosion of a
respective substrate. In another application, the surfacing films
may be used to provide a frictional surface on a walking surface to
prevent slips and falls. In another application, the surfacing
films are disposed on an outer surface of an aircraft component to
reduce drag while in flight. In still another application, the
surfacing films are applied to interior automotive or architectural
surfaces for aesthetic reasons.
[0029] A surfacing film according to one exemplary embodiment is
designated by the numeral 100 and shown in FIG. 1. As shown, the
surfacing film 100 has a plurality of discrete layers. These layers
include, in the following order, a surface layer 102, an
intermediate layer 104, a printed layer 106, a support layer 108,
and an optional adhesive layer 110. The layers are described in
more detail in respective sections below.
[0030] The surface layer 102, the top most layer of FIG. 1, has
first and second major surfaces 112, 114. The surface layer 102 is
shown here directly contacting the adjacent intermediate layer 104,
to which it can be laminated or coated. In some embodiments, the
surface layer 102 and the intermediate layer 104 can be coextruded
layers.
[0031] The first major surface 112 represents an exposed major
surface of the surfacing film 100, although it is to be understood
that this surface could be temporarily covered by a liner or other
protective film for purposes of packaging or storage.
[0032] Optionally and as shown, the first major surface 112 has a
patterned surface, such as a microreplicated surface. In FIG. 1,
the first major surface 112 is characterized by a plurality of
elongated ridges 116. In the embodiment shown, the elongated ridges
116 have a triangular cross-section and are parallel with each
other. Optionally, the elongated ridges 116 extend across the
entirety of the major surface 112, from edge to edge. The ridges
116 are spaced apart from each other by capillary channels 118 to
form a replicated "skip tooth" pattern in which the inter-ridge
spacing is constant.
[0033] The microreplicated surface exemplified here has been shown
to not only reduce frictional drag on primary aircraft structures
when air flow is aligned with the channels, but also provide a
frictional surface. Frictional surfaces can be useful when there is
a need for the surfacing film to function as a surface for foot
traffic. Certain applications require both friction and drag
reduction, such as over-wing walkway films for commercial aircraft.
Microreplicated surfaces can be especially advantageous when they
improve wet friction by wicking moisture or oily substances from
exposed surfaces.
[0034] Frictional performance is generally highest when opposing
surfaces slide along directions perpendicular to the aforementioned
channels. In some embodiments, it can be advantageous for at least
some of the channels to intersect each other thereby providing
enhancement in friction over a wider range of directions.
[0035] While not intended to be limiting, various other examples of
useful geometries that may be present on the provided surfacing
films are described in co-pending U.S. provisional patent
application, Ser. No. 62/115,186 (Swanson et al.), along with U.S.
Pat. No. 5,848,769 (Fronek et al.), U.S. Pat. No. 5,971,326
(Bechert), U.S. Pat. No. 8,668,166 (Rawlings et al.), and U.S.
Patent Publication No. 2012/0080085 (Honeker et al.).
[0036] The surface layer 102 is comprised of a fluoropolymer, such
that the first major surface 112 is a fluoropolymer surface.
Fluoropolymers include fluoroelastomers and fluoroplastics.
Advantageously, these polymers tend to have high thermal stability
and usefulness at high temperatures, and extreme toughness and
flexibility at very low temperatures. Many of these polymers are
almost totally insoluble in a wide variety of organic solvents.
See, for example F. W. Billmeyer, Textbook of Polymer Science, 3rd
ed., pp. 398-403, John Wiley & Sons, New York (1984).
[0037] Useful fluoropolymers can be prepared from a variety of
fluorinated and non-fluorinated monomers, including
perfluorocycloalkene, ethylene ethane, vinyl fluoride
(fluoroethylene), vinylidene fluoride (1,1-difluoroethylene),
tetrafluoroethylene, chlorotrifluoroethylene, propylene,
hexafluoropropylene, perfluoropropylvinylether,
perfluoromethylvinylether, ethylene tetrafluoroethylene,
poly(methyl methacrylate), and combinations thereof.
[0038] In some embodiments, the surface layer 102 is made from a
homopolymer of poly(vinylidene fluoride). In some embodiments, the
surface layer 102 is made from a copolymer of vinylidene fluoride
and hexafluoropropylene. In some embodiments, the surface layer 102
is made from a copolymer of tetrafluoroethylene,
hexafluoropropylene, and vinylidene fluoride, such as sold under
the tradename "THV" from 3M Company, St. Paul, Minn. In some
embodiments, the surface layer 102 can be made from a
THV/polyurethane interpenetrated network, as described in U.S.
Patent Publication No. 2016/0237298 (Jing et al.).
[0039] The surface layer 102 can have any suitable thickness in
keeping with the intended application of the surfacing film 100.
The thickness of the surface layer 102 can be from 4 micrometers to
1024 micrometers, from 75 micrometers to 500 micrometers, from 100
micrometers to 150 micrometers, or in some embodiments, less than,
equal to, or more than 4 micrometers, 5, 6, 7, 8, 9, 10, 12, 14,
16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140,
160, 180, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700,
750, 800, 850, 900, 950, 1000, or 1024 micrometers.
[0040] The intermediate layer 104 is independent from the surface
layer 102 but may be made from any of the same compositions
described with respect to the surface layer. The intermediate layer
104 can, for instance, be made from poly(vinylidene fluoride) or
copolymer or blend thereof. The intermediate layer 104 can also,
however, be made from a polymer or itself incorporate a polymer
layer that has a lesser solvent or chemical resistance than the
surface layer 102, such as a polyurethane, or a polyurethane film
co-extruded with poly(vinylidene fluoride) or copolymer or blend
thereof.
[0041] Referring again to FIG. 1, the intermediate layer 104 has a
microreplicated surface akin to that of the surface layer 102. In
the figure, the respective microreplicated surfaces of these
neighboring layers are mutually aligned. In some cases, mutual
alignment is achieved by uniformly depositing the surface layer 102
onto a pre-shaped intermediate layer 104 from the liquid phase.
Such deposition could take place using any known process, such as a
solution coating process.
[0042] Methods of microreplication that may be used to obtain the
microreplicated surface of the intermediate layer 104 are described
in U.S. Pat. No. 9,285,584 (Hebrink). Known methods include
extrusion replication, embossing, and casting, followed by, if
needed, curing.
[0043] In general, the extrusion replication procedure utilizes a
tool that will impart the negative structure in the polymer
surface. The tooling can be of a variety of forms and materials.
Commonly the form of the tooling will either be a sheet, roll, belt
or roll of surface structured film. The tooling is generally
constructed of material that falls either into the category of
metal or polymer but could potentially include ceramic or other
suitable material. For metal tools, the metal is generally
diamond-machined, embossed, knurled, sandblasted, etc. to form the
surface structure. The structured polymer surface is generally
formed by extrusion replication where a thermoplastic resin is
extruded using standard extrusion equipment and fed through a die
and into a nip with a machined metal tool roll and a rubber roll.
The molten polymer is quenched while in contact with the tool
surface which then releases from the tool roll and is wound on a
roll.
[0044] Another procedure for making structured surfaces is to coat
UV curable acrylate functional resins against a tool followed by
removal of the cross-linked structured film from the tool.
[0045] Another procedure for making structured surfaces is to coat
thermally curable urethane functional resins against a tool
followed by removal of the cross-linked structured film from the
tool. This polyurethane layer can be prepared from the condensation
polymerization of a reaction mixture that comprises a polyol, a
polyisocyanate, and a catalyst. The reaction mixture may also
contain additional components which are not condensation
polymerizable, and may contain at least one UV stabilizer.
[0046] Because the polyurethane polymers described in this
disclosure are formed from the condensation reaction of a polyol
and a polyisocyanate, they contain polyurethane linkages. The
polyurethane polymers formed in this disclosure may contain only
polyurethane linkages or they may contain other optional linkages
such as polyurea linkages, polyester linkages, polyamide linkages,
silicone linkages, acrylic linkages, and the like.
[0047] Any of a number of polyols may be used. Polyols are
hydroxyl-functional materials that have at least two terminal
hydroxyl groups and may be generally described by the structure
HO--B--OH, where the B group may be an aliphatic group, an aromatic
group, or a group containing a combination of aromatic and
aliphatic groups, and may contain a variety of linkages or
functional groups, including additional terminal hydroxyl groups.
The structure HO--B--OH can be a diol or a hydroxyl-capped
prepolymer such as a polyurethane, polyester, polyamide, silicone,
acrylic, or polyurea prepolymer.
[0048] As another possibility, the surface layer 102 could be
initially formed as a free-standing film which is later
thermoformed or otherwise laminated onto the pre-formed
intermediate layer 104. As yet another possibility, the surface
layer 102 could be disposed onto the intermediate layer 104 as a
flat film and subsequently embossed by pressing both films against
a patterned surface, as described above.
[0049] The order in which the layers of the surfacing film 100 are
assembled is not critical. Greater flexibility in manufacturing may
be achieved, for example, if surface layer 102 and intermediate
layer 104 are made separately from the remaining layers 106, 108,
110. The printed layer 106 and support layer 108 may be provided,
for example, as a bilayer that is laminated to the adhesive layer
110, surface layer 102, and/or intermediate layer 104 in a
continuous manufacturing process.
[0050] In some embodiments, the printed layer 106, support layer
108, and adhesive layer 110 are laminated collectively to the
surface layer 102 and intermediate layer 104. In some embodiments,
the printed layer 106, support layer 108, and adhesive layer 110
represent layers of a commercial graphic film, such as available
from 3M Company, St. Paul, Minn.
[0051] The printed layer 106 enables the surfacing film 100 to
communicate information, through alphanumeric text or graphic
images, to an installer or end user. In these cases, it is
preferable for the surface layer 102 and intermediate layer 104 to
be transparent to allow graphic images to be easily observed
through these layers. Content conveyed through the printed layer
106 can be ornamental or functional. Examples of such content
include photographic images, alphanumeric characters, arrows and
symbols, and/or visually aesthetic features.
[0052] If desired, the printed layer 106 can provide visual
contrast with respect to its underlying support layer 108. Visual
contrast may be achieved by incorporating into the printed layer
106 some amount of pigment or dye sufficient to suffuse the printed
layer 106 with color. The support layer 108 optionally includes a
pigment or dye to provide an opaque or semi-opaque background that
provides visual contrast with the printed layer 106.
[0053] While not shown in FIG. 1, the printed layer 106 could also
be a continuous layer extending across most of, or the entirety of,
the major surfaces of the surfacing film 100. In this instance, it
is also possible for the printed layer 106, despite being
continuous, to provide contrast by including areas with different
colors, patterns, or degrees of saturation.
[0054] The composition of the printed layer 106 is not particularly
restricted. In some embodiments, the printed layer 106 is made from
a thermoset polymer. The thermoset polymer can be cured using
actinic radiation, such as ultraviolet (UV) or visible light. In
one exemplary embodiment, the printed layer 106 is comprised of a
polyurethane-based ink. Any of a number of solvent-based inks are
also possible, which may be curable by actinic radiation. As
another option, color can be imparted using a pigment mixed with
one or more binders. Suitable binders can be derived from
polyurethane and/or acrylic polymers.
[0055] The printed layer 106 can disposed on the support layer 108
using any known method, such as ink-jet printing, flexographic
printing, contact printing, thermal transfer printing, and gravure
coating. The printed layer 106 can be continuous or
discontinuous.
[0056] Moreover, the printed layer 106 may be either single-layered
or multi-layered. Each individual layer can be continuous or
discontinuous. The layers can cover the same or different areas
along the support layer 108. Moreover, a given layer can cover none
of, partially cover, or fully cover, another layer. A given layer
may be patterned, if desired.
[0057] Patterned layers may be in forms including, for example,
lines, dots, squares, circles, and combinations thereof. Component
layers of the printed layer 106 can be of uniform or varying
thickness.
[0058] The printed layer 106 preferably has a thickness sufficient
for it to provide visual contrast with itself or the support layer
108 as indicated above. Typical solvent based ink coatings can be 1
to 2 micrometers in thickness. Typical UV-cured ink printings can
be 6 to 12 micrometers in thickness. Typical gravure printings can
be approximately 5 micrometers in thickness, and optionally
disposed on a metallized layer.
[0059] In general, the thickness of the printed layer 106 can be
from 0.5 micrometers to 25 micrometers, from 1 micrometer to 12.5
micrometers, from 1 micrometer to 2 micrometers, or in some
embodiments, less than, equal to, or more than 0.01 micrometers,
0.02, 0.03, 0.05, 0.07, 0.1, 0.15, 0.2, 0.5, 0.7, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, or 50
micrometers.
[0060] As further shown in FIG. 1, the support layer 108 is
disposed between the printed layer 106 and adhesive layer 110. In
cases where the printed layer 106 is relatively thin, the support
layer 108 can help provide strength to the printed layer 106 for
improved structural integrity and web handling in a manufacturing
process.
[0061] The support layer 108 can include one or more polymeric
layers. Particularly suitable polymers for the support layer 108
include polyurethane, polyacrylates and polymethacrylates such as
poly(methyl methacrylate) and butyl acrylate, polycarbonates, and
blends and copolymers thereof. In one embodiment, the support layer
108 is made from a block copolymer of poly(methyl methacrylate) and
poly(butyl acrylate), such as available by Kuraray America Inc.,
Houston, Tex., under the trade designation KURARITY.
[0062] In some embodiments, the support layer 108 is a printable
layer. In some embodiments, the printable layer is an ink-receptive
layer capable of receiving and permanently retaining an ink. While
not shown explicitly in FIG. 1, the support layer 108 may itself be
comprised of two or more layers. For example, the support layer 108
may include two or more polymeric layers.
[0063] The support layer 108 may include one or more non-polymeric
layers. The support layer 108 may be comprised of a polymeric layer
that is at least partially metallized. The metallized surface could
extend across some of all of a major surface of the support layer
108 that faces the printed layer 106. Various processes and
technologies may be employed to obtain a metallized surface.
Metallization processes include vapor deposition, vacuum
metallization, lamination, calendaring, sputtering, electrolytic
plating, evaporating, and flash coating.
[0064] The support layer 108 can have any thickness sufficient to
provide integrity during its handling and printing. The thickness
of the support layer 108 can be from 10 micrometers to 350
micrometers, from 11 micrometers to 170 micrometers, from 12.5
micrometers to 80 micrometers, or in some embodiments, less than,
equal to, or more than 10 micrometers, 12, 14, 16, 18, 20, 25, 30,
35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220,
240, 260, 280, 300, 320, 340, or 350 micrometers.
[0065] Optionally, the surfacing film 100 further includes the
adhesive layer 110. The adhesive layer 110, in preferred
embodiments, is a pressure sensitive adhesive layer. The pressure
sensitive adhesive layer can be normally tacky at ambient
conditions. Suitable pressure sensitive adhesives can be based on
polyacrylates, synthetic and natural rubbers, polybutadiene and
copolymers or polyisoprenes and copolymers. Silicone based
adhesives such as polydimethylsiloxane and polymethylphenylsiloxane
may also be used. Preferred pressure sensitive adhesives include
polyacrylate-based adhesives, which can display advantageous
properties as high degrees of clarity, UV-stability and aging
resistance. Polyacrylate adhesives suitable for protective film
applications are described, for example, in U.S. Pat. No. 4,418,120
(Kealy et al.); RE24,906 (Ulrich); U.S. Pat. No. 4,619,867
(Charbonneau et al.); U.S. Pat. No. 4,835,217 (Haskett et al.); and
International Patent Publication No. WO 87/00189 (Bonk et al.).
[0066] Preferably, a polyacrylate pressure sensitive adhesive
contains a crosslinkable copolymer of a C4-C12 alkylacrylate and an
acrylic acid. The adhesive can be used with or without a
crosslinker. Useful crosslinking reactions include chemical
crosslinking and ionic crosslinking. The chemical crosslinker could
include polyaziridine and/or bisamide and the ionic crosslinker may
include metal ions of aluminum, zinc, zirconium, or a mixture
thereof. A mixture of chemical crosslinker and ionic crosslinker
can also be used. In some embodiments, the polyacrylate pressure
sensitive adhesive includes a tackifier such as rosin ester.
[0067] To adjust properties of the adhesive, the adhesive layer 110
may contain additives such as ground glass, titanium dioxide,
silica, glass beads, waxes, tackifiers, low molecular weight
thermoplastics, oligomeric species, plasticizers, pigments,
metallic flakes and metallic powders as long as they are provided
in an amount that does not unduly degrade the quality of the
adhesive bond to the surface.
[0068] The layers of the surfacing film 100 depicted in FIG. 1 need
not be exclusive. One or more additional layers may be present
between any of the depicted layers or on either major surface of
the surfacing film 100. For example, a release liner can optionally
extend across and contact the adhesive layer 110 to assist in
handling and storage of the surfacing film 100.
[0069] FIG. 2 shows a surfacing film 200 according to a different
embodiment in which the printed layer directly contacts a unitary
layer exposed at the surface of the film. As shown, the surfacing
film 200 includes a surface layer 202 having an outward-facing
major surface 212 that is a patterned surface and an inward-facing
second major surface 214 that is planar. Like the surface layer 102
in the prior embodiment, the surface layer 202 is made from a
fluoropolymer or at least has a fluoropolymer surface.
[0070] The surface layer 202 is coupled to the three underlying
layers shown in FIG. 2--a printed layer 206, support layer 208, and
adhesive layer 210. The configurations and compositions of these
underlying layers are similar to those already described with
respect to the surfacing film 100 of FIG. 1 and need not be
repeated here.
[0071] Achieving strong adhesion to a fluoropolymer surface is a
known technical challenge. The adhesion between the surface layer
202 and the printed layer 206 (and/or support layer 208) can be
enhanced by providing the second major surface 214 of the surface
layer 202 with a nanostructured surface.
[0072] In some embodiments, the nanostructured surface has an
anisotropic nanostructure, in which the topological features have a
height to width (that is, average width) ratio of at least 1.5:1,
at least 2:1, at least 3:1, at least 4:1, or at least 5:1.
[0073] In some embodiments, the nanostructured surface enables some
degree of permeation or interpenetration of the printed layer 206
and/or support layer 208 into the nanostructured surface where
these layers contact each other. The nanostructured surface can
further include undercut features that provide mechanical retention
along the interface between the surface layer 202 and the
underlying printed layer 206/support layer 208. By causing one
layer to be at least partially embedded in the other, or mutually
interlocked, the nanostructured surface enables the surfacing film
200 to resist de-lamination.
[0074] Plasma reactive ion etching is one way to provide a
nanostructured surface on the fluoropolymer surface of the surface
layer 202. Plasma is a partially ionized gaseous or fluid state of
matter containing electrons, ions, neutral molecules, and free
radicals.
[0075] Reactive ion etching can be carried out using any of a
number of methods. One exemplary method uses a rotatable
cylindrical electrode known as a drum electrode and a grounded
counter-electrode within a vacuum vessel. The counter-electrode can
be comprised of the vacuum vessel itself. Gas comprising an etchant
is fed into the vacuum vessel, and plasma is ignited and sustained
between the drum electrode and the grounded counter-electrode. The
conditions are selected so that sufficient ion bombardment is
directed perpendicular to the circumference of the drum. A
continuous substrate comprising a nanoscale mask can then be
wrapped around the circumference of the drum and the matrix can be
etched in the direction normal to the plane of the article. The
exposure time of the article can be controlled to obtain a
predetermined etch depth of the resulting nanostructure.
[0076] Further improvement to adhesion between a fluoropolymer and
a nonfluorinated polymer layer, such as the printed layer 206
and/or support layer 208, can be achieved by surface treatment
followed by applying a layer of a second material such as a
thermoplastic polyamide, such as described in U.S. Pat. No.
6,074,719 (Fukushi et al.).
[0077] Advantageously, the presence of a nanostructured surface on
the second major surface 214 enables a fluoropolymer surface layer
202 to be securely coupled to the underlying printed layer 206 and
support layer 208 without need for an adhesive. The absence of an
interlayer adhesive in turn enables a surfacing film 200 that can
be made thinner and simpler in construction.
[0078] FIG. 3 shows a surfacing film 300 according to another
embodiment that, like surfacing film 200, has a surface layer 302
made in part or in whole from a fluoropolymer, printed layer 306,
support layer 308, and adhesive layer 310. Unlike the prior
surfacing film 200, the surfacing film 300 further includes a tie
layer 303 that assists in bonding the surface layer 302 to the
underlying printed layer 306 and support layer 308.
[0079] In some embodiments, the surface layer 302 and tie layer 303
are coextruded layers. Coextruding the tie layer 303 and the
surface layer 302 from the molten state can allow for some degree
of polymer chain entanglement at the interface between layers and
improve interlayer adhesion.
[0080] The tie layer 303 can be made from any suitable polymer. In
one preferred embodiment, the tie layer 303 is made from a
polyurethane. In another preferred embodiment, the tie layer 303
comprises a polyurethane and poly(vinylidene fluoride). The tie
layer 303 could be blended, copolymerized with, or coextruded from
two or more different polymers. For example, in one embodiment, the
tie layer 303 is a polyurethane film coextruded with
poly(vinylidene fluoride), with the polyurethane side facing the
underlying printed layer 306 and support layer 308.
[0081] The tie layer 303 need not be polymeric. For example, useful
tie layers can be made from sintered nanosilica, as described in
U.S. Patent Publication 2013/0040126 (Pett, et al.).
[0082] The tie layer 303 has a chemical composition that enables
the underlying printed layer 306 and support layer 308 to be heat
laminated to it without need for a nanostructured surface or any
other surface modification.
[0083] The tie layer 303 can have any suitable thickness but can be
made relatively thin. The thickness of the tie layer 303 can be
from 0.1 micrometers to 350 micrometers, from 1 micrometer to 160
micrometers, from 12.5 micrometers to 80 micrometers, or in some
embodiments, less than, equal to, or more than 0.1 micrometers,
0.2, 0.5, 0.7, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35,
40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240,
260, 280, 300, 320, 340, or 350 micrometers.
[0084] Aspects of the remaining layers of the surfacing film 300
are analogous to those already described.
[0085] FIG. 4 shows a surfacing film 400 according to yet another
embodiment in which neither a tie layer nor support layer are
present. The surfacing film 400 can have a surface layer 402 having
first and second major surfaces 412, 414, with characteristics
similar to the surface layer 202 of FIG. 2. The surface layer 202
can be either a fluoropolymer layer or a polymeric layer having a
fluoropolymer outer surface.
[0086] The second major surface 414 is provided with a
nanostructured surface and the printed layer 406 is disposed
directly to the underside of the surface layer 402. The
nanostructured surface, optionally provided by plasma reactive ion
etching as described previously, can enhance interlayer adhesion
thereby helping to secure the printed layer 406 and surface layer
402 to each other.
[0087] The adhesive layer 410 extends across and directly contacts
the printed layer 406. In FIG. 4, the printed layer 406 has been
made continuous to obscure the adhesive layer 410 from view after
the surfacing film 400 has been applied to a substrate.
[0088] FIG. 5 shows a surfacing film 500 according to yet another
embodiment. Like previous embodiments, the surfacing film 500
includes a surface layer 502, printed layer 506, support layer 508,
and adhesive layer 510. In this instance, the printed layer 506 is
a continuous layer, although the printed layer 506 could also be
made discontinuous.
[0089] Disposed between the printed layer 506 and the surface layer
502 is a tie layer 503. The tie layer 503 is made from a
composition that is chemically compatible with both the surface
layer 502 and the printed layer 506, enabling a strong adhesive
bond with each of these neighboring layers. The compositions of
these layers are not particularly restricted. In a preferred
embodiment, the surface layer 502 is a fluoropolymer layer, the tie
layer 503 is a copolymer of poly(vinylidene fluoride) and
poly(methyl methacrylate), and the printed layer 106 is a pigmented
polyurethane-based ink.
[0090] In another embodiment, the fluoropolymer layer is comprised
of THV, a fluorinated copolymer made from hexafluoropropylene,
tetrafluoroethylene, and ethylene monomers (collectively, HTE) or
copolymers of tetrafluoroethylene and ethylene, while the tie layer
is comprised of a polyurethane.
[0091] The underlying layers include a metallized layer 507,
support layer 508, and adhesive layer 510. Compositional and
functional aspects of each of these layers have been reviewed
previously. In this multilayered construction, the printed layer
506 may be first disposed on the tie layer 503 prior to laminating
it to the metallized support layer and any other underlying layers.
As an alternative, the printed layer 506 may be first disposed on
the metallized layer 507 and subsequently laminated to the surface
layer 502 and tie layer 503.
[0092] Advantageously, the provided surfacing films can resist
spontaneous delamination from its substrate even when subjected to
a wide range of harsh environmental conditions, including exposure
to rain, sleet, sea water, cleaning chemicals, and hydraulic
fluids.
[0093] In the event that the provided surfacing film does
delaminate from its substrate, it can be strongly preferred for the
surfacing film to fragment into a multiplicity of pieces, rather
than delaminate in a single piece. This quality can be especially
desirable for surfacing films that are used on aircraft, because
large pieces of surfacing film, once fully detached, are
sufficiently massive to interfere with the operation of fins,
stabilizers, and other moving parts of the aircraft.
[0094] The behavior of the surfacing film upon delamination
correlates with measurable test data, such as delamination peel
strength and tensile strength. Where delamination tends to occur at
the interface between the adhesive layer and the substrate, it can
be preferred for the delamination peel strength of the surfacing
film from the substrate is greater than the tensile strength of the
surfacing film alone, based on the 180.degree. Peel Test (described
in the Examples section below).
[0095] Depending on the composition of the surface layer,
delamination may instead tend to occur at the interface between the
surface film and its underlying layers. In this case, it is
preferable that the delamination peel strength of the surface layer
from the underlying layers is greater than the tensile strength of
the surface layer alone, based on the 180.degree. Peel Test
(described in the Examples section below).
[0096] It was also discovered that the peel behavior of the
provided surfacing films is affected by the relative glass
transition temperatures of neighboring layers within the surfacing
film. Empirical studies have shown that the surfacing film is more
likely to fragment upon delamination when the glass transition
temperature of the surface layer significantly exceeds the glass
transition temperature of its neighboring layer. As has been
demonstrated, the neighboring layer may be a tie layer, a
coextruded polyurethane layer, a printed layer, support layer, or
any combination thereof.
[0097] In the film constructions of FIGS. 1-5, one or more layers
may include additional fillers and other additives. Such additives
may be decorative or utilitarian in nature.
[0098] One or more layers of the surfacing film, for example, may
contain for example an UV absorber. By directly absorbing UV light,
these chemical compounds can reduce the degree of photoinduced
degradation. UV absorbers can effectively absorb light at
wavelengths less than about 400 nm. UV absorbers are typically
included in the UV absorbing layer in an amount that absorb at
least 70 percent, typically 80 percent, more typically greater than
90 percent, or even greater than 99 percent of incident light in a
wavelength region from 180 to 400 nm.
[0099] Typical UV-absorbing layer thicknesses are from 10 to 500
micrometers, although thinner and thicker UV-absorbing layers may
also be used. Typically, the UV-absorber is present in the
UV-absorbing layer in an amount of from 2 to 20 percent by weight,
but lesser and greater levels may also be used.
[0100] An exemplary UV-absorber can be a benzotriazole compound,
5-trifluoromethyl-2-(2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl)-2H-benzo-
-triazole. Other exemplary benzotriazoles include
2-(2-hydroxy-3,5-di-alpha-cumylphenyl)-2H-benzotriazole,
5-chloro-2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-2H-benzothiazole,
5-chloro-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl)-2H-benzotriazole,
2-(3
-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole.
Additional exemplary UV-absorbers include
2(-4,6-diphenyl-1-3,5-triazin-2-yl)-5-hexyloxy-phenol, and those
available from BASF Chemicals Corp. as TINUVIN 1577, TINUVIN 1600,
and TINUVIN 900.
[0101] UV absorbers are broadly described in U.S. Pat. No.
5,450,235 (Smith et al.), U.S. Pat. No. 9,523,516 (Hebrink et al.)
and U.S. Pat. No. 9,285,584 (Hebrink), and U.S. Patent Publication
No. 2014/0009824 (Meitz et al.).
[0102] In some embodiments, it is desirable to use red shifted UV
absorbers (RUVA) which absorb at least 70% (in some embodiments, at
least 80%, particularly preferably greater than 90% of the UV light
in the wavelength region from 180 nm to 400 nm. Typically, it is
desirable if the RUVA is highly soluble in polymers, highly
absorptive, photo-permanent and thermally stable in the temperature
range from 200.degree. C. to 300.degree. C. for extrusion process
to form the protective layer. The RUVA can also be highly suitable
if they can be copolymerizable with monomers to form protective
coating layer by UV curing, gamma ray curing, e-beam curing, or
thermal curing processes.
[0103] RUVAs typically have enhanced spectral coverage in the
long-wave UV region, enabling it to block the high wavelength UV
light that can cause yellowing in polyesters. Typical UV protective
layers have thicknesses in a range from 13 micrometers to 380
micrometers (0.5 mil to 15 mil) with a RUVA loading level of
2-10%). Other preferred benzotriazoles include
2-(2-hydroxy-3,5-di-alpha-cumylphehyl)-2H-benzotriazole,
5-chloro-2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-2H-benzothiazole,
5-chloro-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole,
2-(2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl)-2H-benzotriazole,
2(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2Hbenzotriazole.
Further preferred RUVA includes
2(-4,6-diphenyl-1-3,5-triazin-2-yl)-5-hekyloxy-phenol. Other
exemplary UV absorbers include those available from Ciba Specialty
Chemicals Corporation, Tarrytown, N.Y., under the trade designation
TINUVIN 1577, TINUVIN 1600, TINUVIN 900, and TINUVIN 777.
[0104] Preferred UV absorbers include biphenyltriazines available
from Sukano as masterbatch concentrates under the trade
designations PMMA(TA11-10 MB01), PC(TA28-09 MB02), and PET(TA07-07
MB01).
[0105] One or more layers of the surfacing film may contain a
hindered amine light stabilizer (HALS). HALS, when incorporated
into a polymer or copolymer, can also help the polymer or copolymer
resist adverse effects of actinic radiation (e.g., visible and UV
light) by slowing down photochemically initiated degradation
reactions.
[0106] Exemplary HALS include those available from BASF Chemicals
Corp. under the trade designations CHIMASSORB 944 and TINUVIN 123.
Exemplary antioxidants include those available as IRGANOX 1010 and
ULTRANOX 626 from BASF Chemicals Corp. Further details concerning
HALS are described in U.S. Pat. No. 9,523,516 (Hebrink et al.) and
U.S. Pat. No 9,285,584 (Hebrink), and International Patent
Publication No. WO 2016/105974 (Klun et al.).
[0107] While not intended to be exhaustive, further embodiments of
the provided surfacing films and methods thereof are enumerated as
follows: [0108] 1. A surfacing film comprising: a surface layer
having opposed first and second major surfaces, the first major
surface comprising a fluoropolymer surface and the second major
surface comprising a nanostructured surface; and a printed layer
disposed on the second major surface and at least partially
embedded in the nanostructured surface. [0109] 2. The surfacing
film of embodiment 1, wherein the printed layer comprises a
thermoset polymer. [0110] 3. The surfacing film of embodiment 1 or
2, wherein the nanostructured surface comprises a plasma reactive
ion etched surface. [0111] 4. The surfacing film of any one of
embodiments 1-3, further comprising an adhesive layer extending
across at least a portion of the printed layer. [0112] 5. The
surfacing film of embodiment 4, wherein the adhesive layer is a
pressure-sensitive adhesive layer. [0113] 6. The surfacing film of
embodiment 4 or 5, further comprising a support layer disposed
between the adhesive layer and the printed layer. [0114] 7. The
surfacing film of embodiment 6, wherein the support layer comprises
a polyurethane, polyacrylate, polymethacrylate, polycarbonate, or a
blend or copolymer thereof. [0115] 8. The surfacing film of
embodiment 7, wherein the support layer comprises a block copolymer
comprising poly(methyl methacrylate) and poly(butyl acrylate).
[0116] 9. The surfacing film of any one of embodiments 6-8, wherein
the printed layer is discontinuous. [0117] 10. The surfacing film
of any one of embodiments 6-9, wherein the support layer is
pigmented. [0118] 11. The surfacing film of any one of embodiments
6-10, wherein the support layer is an ink-receptive layer. [0119]
12. The surfacing film of any one of embodiments 1-11, wherein the
first major surface has a microreplicated surface. [0120] 13. The
surfacing film of embodiment 12, wherein the microreplicated
surface comprises a plurality of ridges defining capillary
channels. [0121] 14. A surfacing film comprising: a surface layer
having opposed first and second major surfaces, wherein the first
major surface comprises a fluoropolymer surface; and a
microreplicated intermediate layer in contact with the second major
surface, wherein the fluoropolymer surface has a microreplicated
surface at least partially shaped by the microreplicated
intermediate layer. [0122] 15. The surfacing film of embodiment 14,
wherein the microreplicated surface comprises a plurality of ridges
defining capillary channels. [0123] 16. The surfacing film of
embodiment 14 or 15, wherein the microreplicated intermediate layer
comprises poly(vinylidene fluoride). [0124] 17. The surfacing film
of embodiment 16, wherein the microreplicated intermediate layer
comprises a copolymer or blend of poly(vinylidene fluoride) and
poly(methyl methacrylate). [0125] 18. The surfacing film of
embodiment 14 or 15, wherein the microreplicated intermediate layer
comprises a polyurethane. [0126] 19. The surfacing film of
embodiment 18, wherein the microreplicated intermediate layer
comprises a polyurethane film coextruded with poly(vinylidene
fluoride). [0127] 20. The surfacing film of any one of embodiments
14-19, further comprising a printed layer disposed on the second
major surface, wherein the printed layer is discontinuous. [0128]
21. A surfacing film comprising: a surface layer having opposed
first and second major surfaces, the first major surface comprising
a fluoropolymer surface; a tie layer underlying the surface layer,
wherein the surface layer and the tie layer are coextruded layers;
and a printed layer disposed on the tie layer. [0129] 22. The
surfacing film of embodiment 21, wherein the tie layer comprises
poly(methyl methacrylate). [0130] 23. The surfacing film of
embodiment 22, wherein the tie layer comprises a block copolymer
comprising poly(methyl methacrylate) and poly(butyl acrylate).
[0131] 24. The surfacing film of any one of embodiments 21-23,
wherein the tie layer has a thickness of from 0.1 micrometers to
350 micrometers. [0132] 25. The surfacing film of embodiment 24,
wherein the tie layer has a thickness of from 1 micrometer to 160
micrometers. [0133] 26. The surfacing film of embodiment 25,
wherein the tie layer has a thickness of from 12.5 micrometers to
80 micrometers. [0134] 27. The surfacing film of any one of
embodiments 21-26, wherein the printed layer is discontinuous.
[0135] 28. The surfacing film of any one of embodiments 20-27,
further comprising a support layer disposed on at least a portion
of the printed layer. [0136] 29. The surfacing film of embodiment
28, wherein the support layer comprises polyurethane. [0137] 30.
The surfacing film of embodiment 28, wherein the support layer
comprises poly(methyl methacrylate). [0138] 31. The surfacing film
of embodiment 30, wherein the support layer comprises a block
copolymer comprising poly(methyl methacrylate) and poly(butyl
acrylate). [0139] 32. The surfacing film of any one of embodiments
28-31, wherein the support layer is pigmented. [0140] 33. The
surfacing film of any one of embodiments 28-32, wherein the support
layer is an ink-receptive layer. [0141] 34. The surfacing film of
any one of embodiments 28-33, wherein the support layer has a
thickness of from 10 micrometers to 350 micrometers. [0142] 35. The
surfacing film of embodiment 34, wherein the support layer has a
thickness of from 10 micrometers to 170 micrometers. [0143] 36. The
surfacing film of embodiment 35, wherein the support layer has a
thickness of from 12.5 micrometers to 80 micrometers. [0144] 37.
The surfacing film of any one of embodiments 14-36, further
comprising an adhesive layer extending across the second major
surface of the surface layer. [0145] 38. The surfacing film of
embodiment 37, wherein the adhesive layer is a pressure-sensitive
adhesive layer. [0146] 39. A surfacing film comprising: a surface
layer having opposed first and second major surfaces; and an
adhesive layer extending across the second major surface, wherein
the first major surface comprises a fluoropolymer surface comprises
a microreplicated surface and wherein delamination peel strength of
the surface layer from the remaining layers is greater than the
tensile strength of the surface layer based on the 180.degree. Peel
Test. [0147] 40. The surfacing film of embodiment 39, further
comprising a tie layer disposed between the surface layer and the
adhesive layer. [0148] 41. The surfacing film of embodiment 40,
wherein the tie layer comprises a polyurethane layer. [0149] 42.
The surfacing film of embodiment 40 or 41, wherein the tie layer
has a thickness of from 0.1 micrometers to 350 micrometers. [0150]
43. The surfacing film of embodiment 42, wherein the tie layer has
a thickness of from 1 micrometer to 160 micrometers. [0151] 44. The
surfacing film of embodiment 43, wherein the tie layer has a
thickness of from 12.5 micrometers to 80 micrometers. [0152] 45.
The surfacing film of any one of embodiments 1-44, wherein
delamination peel strength of the surface layer from the remaining
layers exceeds the tensile strength of the surface layer based on
the 180.degree. Peel Test. [0153] 46. The surfacing film of any one
of embodiments 1-45, wherein the fluoropolymer surface comprises
poly(vinylidene fluoride) homopolymer. [0154] 47. The surfacing
film of any one of embodiments 1-45, wherein the fluoropolymer
surface comprises a copolymer of vinylidene fluoride and
hexafluoropropylene. [0155] 48. The surfacing film of any one of
embodiments 1-45, wherein the fluoropolymer surface comprises a
copolymer of tetrafluoroethylene, hexafluoropropylene, and
vinylidene fluoride. [0156] 49. The surfacing film of any one of
embodiments 1-45, wherein the fluoropolymer surface comprises a
copolymer of hexafluoropropylene, tetrafluoroethylene, and
ethylene. [0157] 50. The surfacing film of any one of embodiments
1-49, wherein the surface layer has a thickness of from 4
micrometers to 1024 micrometers. [0158] 51. The surfacing film of
embodiment 50, wherein the surface layer has a thickness of from 75
micrometers to 500 micrometers. [0159] 52. The surfacing film of
embodiment 51, wherein the surface layer has a thickness of from
100 micrometers to 150 micrometers. [0160] 53. The surfacing film
of any one of embodiments 1-52, wherein the fluoropolymer surface
comprises a plurality of ridges arranged in a replicated skip tooth
pattern. [0161] 54. The surfacing film of any one of embodiments
1-13 and 20-36, wherein the printed layer has a thickness of from
0.5 micrometers to 50 micrometers. [0162] 55. The surfacing film of
embodiment 54, wherein the printed layer has a thickness of from 1
micrometer to 25 micrometers. [0163] 56. The surfacing film of
embodiment 55, wherein the printed layer has a thickness of from 1
micrometer to 6 micrometers. [0164] 57. The surfacing film of any
one of embodiments 1-13, 20-36 and 54-56, wherein the printed layer
comprises a polyurethane-based ink. [0165] 58. The surfacing film
of any one of embodiments 1-8, 10-13, 21-26, 28-38, and 54-57,
wherein the printed layer is a continuous layer and gravure-coated.
[0166] 59. The surfacing film of any one of embodiments 1-58,
wherein the glass transition temperature of the surface layer
exceeds the glass transition temperature of its neighboring layer.
[0167] 60. The surfacing film of any one of embodiments 1-59,
wherein one or more layers of the surfacing film comprises an
ultraviolet absorber. [0168] 61. The surfacing film of any one of
embodiments 1-60, wherein one or more layers of the surfacing film
comprises a hindered amine light stabilizer. [0169] 62. The
surfacing film of any one of embodiments 6-11 and 28-36, wherein
the support layer has a major surface facing the printed layer that
is at least partially metallized. [0170] 63. The surfacing film of
any one of embodiments 1-62, wherein the first major surface has a
microreplicated surface comprised of a plurality of ridges defining
channels, and further wherein at least some of the channels
intersect each other. [0171] 64. A method of using the surfacing
film of any one of embodiments 1-63, comprising applying the
surfacing film to an outer surface of an aircraft component to
enhance friction. [0172] 65. A method of making a surfacing film,
the method comprising: disposing a printed layer on a support layer
to provide a bilayer; and laminating the bilayer to a surface layer
having opposing first and second major surfaces, wherein the first
major surface comprises a fluoropolymer surface and the second
major surface has a nanostructured surface and is in contact with
the printed layer. [0173] 66. The method of making the surfacing
film of embodiment 65, wherein the step of laminating the bilayer
to the surface layer does not use an adhesive.
[0174] Objects and advantages of this disclosure are further
illustrated by the following non-limiting examples, but the
particular materials and amounts thereof recited in these examples,
as well as other conditions and details, should not be construed to
unduly limit this disclosure.
EXAMPLES
[0175] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by
weight.
TABLE-US-00001 TABLE 1 MATERIALS Designation Description Source
PVDF 6008 A fluoropolymer made from vinylidene 3M Co., St. Paul, MN
fluoride ("VDF") monomers, available under the trade designation 3M
DYNEON PVDF 6008 CoPVDF 11010 A fluorinated copolymer made from 3M
Co., St. Paul, MN VDF and hexafluoropropylene ("HFP") monomers,
available under the trade designation 3M DYNEON CoPVDF 11010 THV
500 A fluorinated copolymer made from 3M Co., St. Paul, MN
tetrafluoroethylene ("TFE"), HFP, and VDF monomers, available under
the trade designation 3M DYNEON FLUOROPLASTIC THV 500GZ HTE 1705 A
fluorinated copolymer made from 3M Co., St. Paul, MN HFP, TFE, and
ethylene monomers, available under the trade designation 3M DYNEON
HTE 1705 TEXIN 285 A thermoplastic polyurethane, available Lubrizol
Corp., under the trade designation TEXIN 285 Wickliffe, OH PP A
polypropylene homopolymer Atofina Chemicals, Inc., Philadelphia, PA
ETFE A fluorinated copolymer made from TFE 3M Co., St. Paul, MN and
ethylene, available under the trade designation 3M DYNEON ETFE PU
TAPE 8671 A white, printable polyurethane ("PU") 3M Co., St. Paul,
MN tape (including a 12 mil (about 305 micrometer) polyurethane
layer and a 2 mil (about 51 micrometer) pressure sensitive adhesive
layer), available under the trade designation 3M POLYURETHANE
PROTECTIVE TAPE 8671 GW PU TAPE 8673 A clear, printable
polyurethane tape 3M Co., St. Paul, MN (including a 12 mil (about
305 micrometer) polyurethane layer and a 2 mil (about 51
micrometer) pressure sensitive adhesive layer), available under the
trade designation 3M POLYURETHANE PROTECTIVE TAPE 8673 PU TAPE 8674
A clear, printable polyurethane tape 3M Co., St. Paul, MN
(including a 6 mil (about 152 micrometer) polyurethane layer and a
2 mil (about 51 micrometer) pressure sensitive adhesive layer),
available under the trade designation 3M POLYURETHANE PROTECTIVE
TAPE 8674 9802 UV INK A UV curable ink available under the 3M Co.,
St. Paul, MN trade designation 3M 9802 OPAQUE BLACK SCREEN PRINTING
UV INK SKYDROL LD-4 A fire resistant hydraulic fluid, available
Eastman Chemical under the trade designation SKYDROL Companies,
Kingsport, LD-4 TN
Test Methods
180-DEGREE PEEL TEST
[0176] The 180-DEGREE PEEL TEST was performed according to ASTM
D1876-08. Peel tests were performed at temperatures of +10.degree.
C., 0.degree. C., -10.degree. C., -20.degree. C., -30.degree. C.,
and -40.degree. C., using a temperature equilibration time of 5
minutes prior to conducting the peel measurements on an INSTRON
instrument. Test samples were cut to 1 inch (2.5 cm) wide by 6 inch
(15 cm) long strips. The tests were carried out using an INSTRON
instrument, for a 180 degree peel. The peel test values were for
the separation between the cover layer and the printed support
layer (e.g., 3M 8671) of test samples, and were reported as
pound-force per inch (lbs/in; values were also converted to Newtons
per cm (N/cm) by multiplying lbs/in value by 1.75 (using 1
lb/in=1.75 N/cm)).
Method for Nanostructure Creation by Reactive Ion Etching (Plasma
Treatment):
[0177] The nanostructures of this invention were generated out by
using a homebuilt plasma treatment system described in detail in
U.S. Pat. No. 5,888,594 (David et al.), with some modifications.
The width of the drum electrode was increased to 42.5 inches (108
cm) and the separation between the two compartments within the
plasma system was removed so that all the pumping was carried out
by means of the turbo-molecular pump and thus operating at a
process pressure of around 10 mTorr (about 1.3 Pa). A roll of the
polymeric film to be treated was mounted within the chamber, the
film wrapped around the drum electrode and secured to the take up
roll on the opposite side of the drum. The unwind tension and
take-up tension were both maintained at 6 pounds (10 N) and 14
pounds (10 N), respectively. The chamber door was closed and the
chamber was pumped down to a base pressure of 5.times.10.sup.-4
torr (about 0.07 Pa). For the plasma treatment,
hexamethyldisiloxane (HMDSO) and oxygen were introduced at a flow
rate of 60 standard cm.sup.3/min and 750 standard cm.sup.3/min
respectively, and the operating pressure was nominally at 9 mTorr
(about 1.2 Pa). Plasma was turned on at a power of 7500 watts by
applying RF power to the drum and the drum rotation was initiated
so that the film was transported at a speed of 10 feet/min (about
3.0 m/min.). The run was continued until the entire length of the
film on the roll was completed.
[0178] After the entire roll of polymeric film was treated in the
above manner, the RF power was disabled, oxygen flow stopped,
chamber vented to the atmosphere, and the roll taken out of the
plasma system for further processing.
Comparative Example 1
[0179] Painted PU TAPE 8671 tape (painted with 9802 UV INK),
thermally laminated onto a 12-mil (305-micrometer) thick clear,
flat PU tape (PU TAPE 8673, without adhesive).
Comparative Example 2
[0180] Comparative Example 1 with an added 1-mil (25-micrometer)
thick flat THV500 film (fluoropolymer film) placed on top of a
portion of the Comparative Example 1 layer.
Example 1
Microreplicated Film made Via Extrusion of PVDF 6008
[0181] PVDF 6008 was extruded using a 25 mm twin screw extruder at
18.2 kg/hr (40 pph) through a flat film die onto a patterned
casting roll. The surface structure on the polymeric film was
formed by contacting the outer major surface of the first layer of
the polymeric film with a patterned casting roll at 82.degree. C.
and using a rubber nip roll applying a nip force of 5.965 kg per cm
(33 pounds per lineal inch) of film width and a line speed of 5.5
meters per minute (18 feet per minute). Patterned casting roll
targeted a "skip tooth" pattern, with 80 micrometer tall linear
prism features having an 80 micrometer base and a peak to peak
spacing of 150. The included peak angle on the microreplicated
features of the casting roll was 53 degrees. Extrusion replicated
PVDF 6008 made using this process and patterned casting roll had
rounded tips with a peak to valley height of 46 micrometers.
Example 2
Microreplicated Film made Via Extrusion of PVDF 6008, Plus Reactive
Ion Etching Treatment
[0182] The microreplicated film of Example 1 was treated with the
reactive ion etching treatment described above, on the major
surface opposite the microreplicated surface.
Example 3
Microreplicated Film made Via Extrusion of CoPVDF 11010
[0183] CoPVDF 11010 was extruded using a 25 mm twin screw extruder
at 18.2 kg/hr (40 pph) through a flat film die onto a patterned
casting roll. The surface structure on the polymeric film was
formed by contacting the outer major surface of the first layer of
the polymeric film with a patterned casting roll at 82.degree. C.
and using a rubber nip roll applying a nip force of 5.965 kg per cm
(33 pounds per lineal inch) of film width and a line speed of 5.5
meters per minute (18 feet per minute). Patterned casting roll
targeted a "skip tooth" pattern, with 80 micrometer tall linear
prism features having an 80 micrometer base and spaced apart by 150
micrometers. The included peak angle on the microreplicated
features was 53 degrees. Extrusion replicated CoPVDF 11010 made
using this process and patterned casting roll had rounded tips with
a peak to valley height of 46 micrometers, as measured by confocal
microscopy.
Example 4
Microreplicated Film made Via Extrusion of CoPVDF 11010, Plus
Reactive Ion Etching Treatment
[0184] The microreplicated film of Example 3 was treated with the
reactive ion etching treatment described above, on the major
surface opposite the microreplicated surface.
Example 5
Microreplicated Multilayer Film made Via Coextrusion of CoPVDF
11010, TEXIN 285, and PP
[0185] A multilayer extrusion replicated polymeric film was made
using a 3 layer multi-manifold die to coextrude a first layer of
PVDF 11010, a second layer of a thermoplastic polyurethane TEXIN
285, and a third layer of a homopolymer polypropylene (PP). The
PVDF 11010 was fed to the bottom manifold of the multi-manifold die
with a 25 mm twin screw extruder at 18.2 kg/hr. (40 lbs./hr.). The
TEXIN 285 was fed to the center manifold of the multi-manifold die
with a 31 mm single screw extruder at 18.2 kg/hr. (40 lbs./hr.).
The PP was fed to the top manifold of multi-manifold die with a 31
mm single screw extruder at 18.2 kg/hr. (40 lbs./hr.). The
multilayer polymeric film was cast onto a chilled roll at 5.54
meters/minute (18 fpm) to a thickness of 75 micrometers. The
surface structure on the polymeric film was formed by contacting
the outer major surface of the first layer of the polymeric film
(i.e., the PVDF 11010 layer) with a patterned casting roll at
82.degree. C. and using a rubber nip roll applying a nip force of
5.965 kg per cm (33 pounds per lineal inch) of film width and a
line speed of 5.5 meters per minute (18 feet per minute). Patterned
casting roll targeted a "skip tooth" pattern, with 80 micrometer
tall linear prism features having an 80 micrometer base and spaced
apart by 150 micrometers. The included peak angle on the
microreplicated features was 53 degrees. The extrusion replicated
multilayer film made using this process and patterned casting roll
had rounded tips with a peak to valley height of 64
micrometers.
Example 6
Microreplicated Film made Via Hot Pressing of a THV500 Film
[0186] To make this film, an acrylate tool having a continuous
riblet pattern with peaks 100 micrometer tall, and peak-to-peak
spacing of 100 micrometers and having included peak angle on the
microreplicated features of 53 degrees was used. The acrylate tool
was placed on top of a 5-mil (about 130 micrometers) thick THV500
film, inside a vacuum bag. A vacuum was drawn continuously and the
bag was placed inside a 350.degree. F. (177.degree. C.) oven for 1
hour. After sample temperature cooled to less than 150.degree. F.
(66.degree. C.), the embossed THV500 film was peeled away from the
acrylate tool, without leaving acrylate residue on the THV500
film's riblet surface.
Example 7
Microreplicated Film, made Via Extrusion of HTE 1705
[0187] HTE 1705 was extruded using a 25 mm twin screw extruder at
18.2 kg/hr (40 pph) through a flat film die onto a patterned
casting roll. The surface structure on the polymeric film was
formed by contacting the outer major surface of the first layer of
the polymeric film with a patterned casting roll at 82.degree. C.
and using a rubber nip roll applying a nip force of 5.965 kg per cm
(33 pounds per lineal inch) of film width and a line speed of 5.5
meters per minute (18 feet per minute). Patterned casting roll
targeted a "skip tooth" pattern, with 80 micrometer tall linear
prism features having an 80 micrometer base and spaced apart by 150
micrometers. The included peak angle on the microreplicated
features was 53 degrees.
[0188] Extrusion replicated HTE 1705 made using this process and
patterned casting roll had rounded tips with a peak to valley
height of 46 micrometers.
Example 8
Multilayer Microreplicated Film made Via Coextrusion of THV815,
TEXIN 285, and PP
[0189] A multilayer extrusion replicated polymeric film was made
using a 3 layer multi-manifold die to coextrude a first layer of
THV815, a second layer of thermoplastic polyurethane TEXIN 285, and
a third layer of a homopolymer polypropylene (PP). The THV815 was
fed to the bottom manifold of the multi-manifold die with a 25 mm
twin screw extruder at 18.2 kg/hr. (40 lbs./hr.). The TEXIN 285 was
fed to the center manifold of the multi-manifold die with a 31 mm
single screw extruder at 18.2 kg/hr. (40 lbs./hr.). The PP was fed
to the top manifold of multi-manifold die with a 31 mm single screw
extruder at 18.2 kg/hr. (40 lbs./hr.). The multilayer polymeric
film was cast onto a chilled roll at 5.54 meters/minute (18 fpm) to
a thickness of 75 micrometers. The surface structure on the
polymeric film was formed by contacting the outer major surface of
the first layer of the polymeric film with a patterned casting roll
at 82.degree. C. and using a rubber nip roll applying a nip force
of 5.965 kg per cm (33 pounds per lineal inch) of film width and a
line speed of 5.5 meters per minute (18 feet per minute). Patterned
casting roll had 80 micrometer tall linear prism features having an
80 micrometer base and spaced apart by 150 micrometers. The
included peak angle on the microreplicated features was 53 degrees.
Extrusion replicated THV815 made using this process and patterned
casting roll had rounded tips with a peak to valley height of 64
micrometers.
Example 9
[0190] Starting with the film of Comparative Example 1, a riblet
structure was added as follows: an acrylate tool having a
continuous riblet pattern with peaks 100 micrometer tall, and
peak-to-peak spacing of 100 micrometers and having included peak
angle on the microreplicated features of 53 degrees was used for
embossing a polypropylene film (12 mils thick), and then this
embossed polypropylene film was used as a tool to emboss the
polyurethane film of Comparative Example 1. The microreplicated
surface of this embossed polyurethane film was then coated with the
THV/PU interpenetrated network (2 mils thick) described in
WO2015/069502, followed by treatment in a 150 C oven for 3 minutes.
This was an exemplary embodiment of the film 100 shown in FIG.
1.
Example 10
[0191] The microreplicated film of Example 1 was heat laminated
(280.degree. F., 138.degree. C.) onto a printed 8671 polyurethane
film.
Example 11
[0192] The microreplicated film of Example 2 was heat laminated
(280.degree. F., 138.degree. C.) with a printed 8671 polyurethane
film. This was an exemplary embodiment of the film 200 shown in
FIG. 2, including a surface 214 having reactive ion treatment.
Example 12
[0193] The microreplicated film of Example 3 was heat laminated
(280.degree. F., 138.degree. C.) with a printed 8671 polyurethane
film.
Example 13
[0194] This microreplicated film of Example 4 was heat laminated
(280.degree. F., 140.degree. C.) with a printed 8671 polyurethane
film. Confocal microscopy confirmed that the riblet microstructure
survived the lamination process, having an average peak to valley
height of about 45 micrometers. This was an exemplary embodiment of
the film 200 shown in FIG. 2, including a surface 214 having
reactive ion treatment.
Example 14
[0195] The microreplicated film of Example 5 was heat laminated
(280 F, 140 C) with a printed 8671 PU film. This was an exemplary
embodiment of the film 300 shown in FIG. 3
SKYDROL Resistance Test 1 (and results)
[0196] In this test, a droplet of SKYDROL LD-4 was placed on top of
the test film sample, so that the SKYDROL LD-4 didn't leak via the
edge of the film sample to attack the polyurethane or adhesives
layers underneath the top surface of the film sample.
A 2 ml drop of SKYDROL LD-4 each on top of Comparative Example 1
and Comparative Example 2. After 44 hours, visually we could see
the Comparative Example 1's polyurethane top layer blister and
delaminated from the ink layer. The ink layer also swelled and
blistered. After 44 hours, the SKYDROL LD-4 still sat on top of the
THV500 layer on Comparative Sample Comparative Example 2. After 7
days, visually we still saw the SKYDROL LD-4 sat on top of the
THV500 layer, with no damage to the printed pattern underneath.
[0197] We learned from Comparative Example 1 that the 1-mil (about
25 micrometers) thick THV500 film sample was able to withstand
SKYDROL LD-4 for at least a week. A 12-mil (about 305 micrometers)
thick PU layer was not able to withstand SKYDROL LD-4 for 1 day, as
shown in FIG. 6.
[0198] In FIG. 6, the initial condition of the unprotected PU layer
(upper left) was visually unaffected by the droplet of SKYDROL
LD-4, but after 44 hours, the condition of the unprotected PU layer
(lower left) was visually degraded in the region of the SKYDROL
LD-4 liquid. On the right side of FIG. 6, no degradation of the PU
layer was visually observed, in the region covered by a
fluoropolymer ("FP") cover tape (i.e., the Comparative Example 2
construction, where the fluoropolymer was THV500).
SKYDROL Resistance Test 2 (and results)
[0199] A CONTROLTAC liner was peeled from the bottom of both
samples Example 11 and Example 13, and then taped Example 11 and
Example 13 samples to 4 inch by 4 inch (10 cm by 10 cm) aluminum
coupons. The edges of the tapes were sealed with 3M ES2000 edge
seal ("3M EDGE SEALER ES2000", 3M Co., St. Paul, Minn.). To
eliminate the edge effect caused by the limited SKYDROL LD-4
resistivity by ES2000, sufficient ES2000 to form a 3 mm
high.times.4 mm wide edge. The test coupon was then left in room
condition for 72 hours to completely cure the ES2000.
[0200] The test coupons were next submerged in SKYDROL LD4 bath for
7 days. After 7 days, there was visually no damage or blisters to
the samples Example 11 and Example 13. When tweezers were manually
scrubbed across the film surface, a squeeze sound could be heard,
consistent with intact riblet patterns.
[0201] After Example 11 and Example 13 were submerged in SKYDROL
LD-4 for 31 days, there was no visually observable damage to the
samples. When tweezers were manually scrubbed across the film
surface, a squeeze sound could be heard, consistent with intact
riblet patterns.
[0202] After Example 11 and Example 13 were submerged in SKYDROL
LD-4 for 90 days, the ES2000 edge seal failed. The SKYDROL LD-4
attacked the polyurethane layer underneath the fluoropolymer layer.
However, the riblets on the PVDF and coPVDF films could still be
felt by manually scrubbing the surface of the film with
tweezers.
SKYDROL Resistance Test 3 (and results)
[0203] A 1 ml drop of SKYDROL LD-4 was placed on the film surface
of EXAMPLE 9. After 1 day, visual observation showed that the
SKYDROL LD-4 leaked underneath the TPU/THV coating and attacked the
PU layer. However, in some spots, the SKYDROL LD-4 still remained
on top of the film.
Peel Test Data
[0204] The tapes of Examples 10 to 14 were tested in the 180-DEGREE
PEEL TEST, with results as summarized in Tables 2A and 2B
below.
TABLE-US-00002 TABLE 2A +10.degree. C. +10.degree. C. 0.degree. C.
0.degree. C. -10.degree. C. -10.degree. C. peak force, average peel
peak force, average peel peak force, average peel lbs/in force,
lbs/in lbs/in force, lbs/in lbs/in force, lbs/in Sample (N/cm)
(N/cm) (N/cm) (N/cm) (N/cm) (N/cm) EX-10 0.24 (0.42) 0.087 (0.15)
0.44 (0.77) 0.080 (0.14) 0.32 (0.56) 0.083 (0.15) EX-11 10.0 (17.5)
break 9.95 (17.4) break 3.21 (5.62) 0.52 (0.91)* EX-12 0.44 (0.77)
0.13 (0.23) 1.69 (2.96) 0.22 (0.39) 1.05 (1.84) 0.16 (0.28) EX-13
21.2 (37.2) 19.3 (33.7)** 26.1 (45.7) break 26.3 (46.1) break EX-14
16.5 (28.9) 11.9 (20.9) 14.5 (25.3) 12.8 (22.4) 14.7 (25.6) 11.4
(19.9)
TABLE-US-00003 TABLE 2B -20.degree. C. -20.degree. C. -30.degree.
C. -30.degree. C. -40.degree. C. -40.degree. C. peak force, average
peel peak force, average peel peak force, average peel lbs/in
force, lbs/in lbs/in force, lbs/in lbs/in force, lbs/in Sample
(N/cm) (N/cm) (N/cm) (N/cm) (N/cm) (N/cm) EX-10 0.24 (0.42) 0.087
(0.15) 0.17 (0.30) 0.13 (0.23) 0.43 (0.75) 0.30 (0.53) EX-11 2.37
(4.15) 0.48 (0.84) 1.58 (2.77) 0.69 (1.2) 0.76 (1.33) 0.56 (0.98)
EX-12 0.61 (1.1) 0.18 (0.32) 0.85 (1.5) 0.49 (0.86) 0.49 (0.86)
0.45 (0.79) EX-13 13.4 (23.5) break 18.0 (31.5) break 15.9 (27.8)
break EX-14 14.6 (25.5) 12.0 (21.0) 14.4 (25.2) 14.0 (24.4)** 14.9
(26.1) break
[0205] In Tables 2A and 2B: [0206] "*"=one of three tape samples
broke during the test; [0207] "**"=two of three tape samples broke
during the test; and [0208] "break"=all three tape samples broke
during the test.
[0209] All cited references, patents, and patent applications in
the above application for letters patent are herein incorporated by
reference in their entirety in a consistent manner. In the event of
inconsistencies or contradictions between portions of the
incorporated references and this application, the information in
the preceding description shall control. The preceding description,
given in order to enable one of ordinary skill in the art to
practice the claimed disclosure, is not to be construed as limiting
the scope of the disclosure, which is defined by the claims and all
equivalents thereto.
* * * * *